scholarly journals Effects of Barrier Stiffness on Debris Flow Dynamic Impact—II: Numerical Simulation

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 182
Author(s):  
Yu Huang ◽  
Xiaoyan Jin ◽  
Junji Ji
Keyword(s):  
Debris Flow ◽  
Smoothed Particle Hydrodynamics ◽  
Impact Force ◽  
Time History ◽  
Appreciable Effect ◽  
Engineering Structures ◽  
Dynamic Component ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

The destructive and impactful forces of debris flow commonly causes local damage to engineering structures. The effect of a deformable barrier on the impact dynamics is important in engineering design. In this study, a flow–structure coupled with Smoothed Particle Hydrodynamics model was presented to investigate the effects of barrier stiffness on the debris impact. A comparison of the results of physical tests and simulation results revealed that the proposed smoothed particle hydrodynamics model effectively reproduces the flow kinematics and time history of the impact force. Even slight deflections of the deformable barrier lead to obvious attenuation of the peak impact pressure. Additionally, deformable barriers with lower stiffness tend to deform more downstream upon loading, shifting the deposited sand toward the active failure mode and generating less static earth pressure. When the debris flow has a higher frontal velocity, the impact force on the barrier is dominated by the dynamic component and there is an appreciable effect of the stiffness of the deformable barrier on load attenuation.

Numerical study on debris flow in step-pools channel using smoothed particle hydrodynamics method

2020 ◽  
Author(s):  
Shuai Li ◽  
Xiaoqing Chen ◽  
Chong Peng ◽  
Jiangang Chen
Keyword(s):  
Debris Flow ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Impact Force ◽  
Numerical Study ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Smoothed Particle Hydrodynamics Method ◽  
The Impact ◽  
Peak Impact Force

<p>Drainage channel with step-pool systems are widely used to control debris flow. However, the blocking of debris flow often gives rise to local damage at the steps and baffles. Hence, the estimation of impact force of debris flow is crucial for design step-pools channel. This paper presents a numerical study on the impact behavior of debris flows using SPH (Smoothed Particle Hydrodynamics) method. Some important parameters, such as the baffle shape (square, triangle, and trapezoid) and the densities of debris flows are considered to examine their influence on the impact force. The results show that the largest peak impact force is obtained at the second last baffle, rather than the first baffle. Moreover, the square baffle gives rise to the largest impact force whereas the triangle baffle bears the smallest one among the three baffles. Generally, the peak impact force increases with increasing the inflow density. However, a threshold density, beyond which the peak impact force will decrease, is suggested by the simulations. Based on the numerical results, an improved expression to predict the impact force considering the inclined angle of baffle is proposed.</p>

scholarly journals Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

Modeling Hypervelocity Impacts Using Smoothed Particle Hydrodynamics

2018 ◽  
Author(s):  
M. Ganser ◽  
B. van der Linden ◽  
C. G. Giannopapa
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Large Deformations ◽  
Hypervelocity Impact ◽  
Density Fluctuations ◽  
Computational Domain ◽  
Simulation Tool ◽  
Hypervelocity Impacts ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

Hypervelocity impacts occur in outer space where debris and micrometeorites with a velocity of 2 km/s endanger spacecraft and satellites. A proper shield design, e.g. a laminated structure, is necessary to increase the protection capabilities. High velocities result in massive damages. The resulting large deformations can hardly be tackled with mesh based discretization methods. Smoothed Particle Hydrodynamics (SPH), a Lagrangian meshless scheme, can resolve large topological changes whereas it still follows the continuous formulation. Derived by variational principles, SPH is able to capture large density fluctuations associated with hypervelocity impacts correctly. Although the impact region is locally limited, a much bigger domain has to be discretized because of strong outgoing pressure waves. A truncation of the computational domain is preferable to save computational power, but this leads to artificial reflections which influence the real physics. In this paper, hypervelocity impact (HVI) is modelled by means of basic conservation assumptions leading to the Euler equations of fluid dynamics accompanied by the Mie-Grueneisen equation of state. The newly developed simulation tool SPHlab presented in this work utilizes the discretization method smoothed particle hydrodynamics (SPH) to capture large deformations. The model is validated through a number of test cases. Different approaches are presented for non-reflecting boundaries in order to tackle artificial reflections on a computational truncated domain. To simulate an HVI, the leading continuous equations are derived and the simulation tool SPHlab is developed. The method of characteristics allows to define proper boundary fluxes by removing the inwards travelling information. One- and two-dimensional model problems are examined which show excellent absorption behaviour. An hypervelocity impact into a laminated shield is simulated and analysed and a simple damage model is introduced to model a spallation failure mode.

scholarly journals Application of Smoothed Particle Hydrodynamics (SPH) for the Simulation of Flow-like Landslides on 3D Terrains

2022 ◽  
Author(s):  
Binghui Cui ◽  
Liaojun Zhang
Keyword(s):  
Risk Assessment ◽  
Smoothed Particle Hydrodynamics ◽  
Disaster Mitigation ◽  
Sph Method ◽  
Landslide Event ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Simulation Results ◽  
Mitigation Design ◽  
The Impact

Abstract Flow-type landslide is one type of landslide that generally exhibits characteristics of high flow velocities, long jump distances, and poor predictability. Simulation of it facilitates propagation analysis and provides solutions for risk assessment and mitigation design. The smoothed particle hydrodynamics (SPH) method has been successfully applied to the simulation of two-dimensional (2D) and three-dimensional (3D) flow-like landslides. However, the influence of boundary resistance on the whole process of landslide failure is rarely discussed. In this study, a boundary algorithm considering the friction is proposed, and integrated into the boundary condition of the SPH method, and its accuracy is verified. Moreover, the Navier-Stokes equation combined with the non-Newtonian fluid rheology model was utilized to solve the dynamic behavior of the flow-like landslide. To verify its performance, the Shuicheng landslide event, which occurred in Guizhou, China, was taken as a case study. In the 2D simulation, a sensitivity analysis was conducted, and the results showed that the shearing strength parameters have more influence on the computation accuracy in comparison with the coefficient of viscosity. Afterwards, the dynamic characteristics of the landslide, such as the velocity and the impact area, were analyzed in the 3D simulation. The simulation results are in good agreement with the field investigations. The simulation results demonstrate that the SPH method performs well in reproducing the landslide process, and facilitates the analysis of landslide characteristics as well as the affected areas, which provides a scientific basis for conducting the risk assessment and disaster mitigation design.

Analysis of surface-erosion mechanism due to impacts of freely rotating angular particles using smoothed particle hydrodynamics erosion model

2017 ◽  
Vol 231 (12) ◽  
pp. 1537-1551 ◽  
Author(s):  
Xiangwei Dong ◽  
Zengliang Li ◽  
Qi Zhang ◽  
Wei Zeng ◽  
G.R. Liu
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Impact Angle ◽  
Surface Erosion ◽  
Free Rotation ◽  
Erosion Model ◽  
Erosion Mechanism ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact ◽  
Angular Particles

The free rotation of an angular particle during its impact on ductile surfaces is an important factor that influences the erosion mechanism. However, the phenomenon cannot be easily revealed experimentally because the incident conditions cannot be accurately controlled. In this study, a novel erosion model based on smoothed particle hydrodynamics method is proposed to simulate single and multiple impacts of particles with specified angularities on a ductile surface. The model can simulate a particle having free rotation during the impact process and initial rotation prior to the impact. The results show that the impact angle and initial orientation significantly affect the tumbling behavior, which determines the erosion mechanism. Moreover, the initial rotation is investigated by assigning an initial angular velocity to the particle at the onset of impact. The proposed smoothed particle hydrodynamics erosion model is proven to be a promising complementary method that supports experimental techniques. This study provides insight for understanding the fundamental mechanisms of surface erosion due to angular particles.

scholarly journals Dynamic Force on an Elbow Caused by a Traveling Liquid Slug

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Darcy Q. Hou ◽  
Arris S. Tijsseling ◽  
Zafer Bozkus
Keyword(s):  
Experimental Data ◽  
Impact Force ◽  
Initial Conditions ◽  
Flow Direction ◽  
Dynamic Force ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
1D Model ◽  
High Reynolds ◽  
The Impact

The impact force on an elbow induced by traveling isolated liquid slugs in a horizontal pipeline is studied. A literature review reveals that the force on the elbow is mainly due to momentum transfer in changing the fluid flow direction around the elbow. Therefore, to accurately calculate the magnitude and duration of the impact force, the slug arrival velocity at the elbow needs to be well predicted. The hydrodynamic behavior of the slug passing through the elbow needs to be properly modeled too. A combination of 1D and 2D models is used in this paper to analyze this problem. The 1D model is used to predict the slug motion in the horizontal pipeline. With the obtained slug arrival velocity, slug length, and driving air pressure as initial conditions, the 2D Euler equations are solved by the smoothed particle hydrodynamics (SPH) method to analyze the slug dynamics at the elbow. The 2D SPH solution matches experimental data and clearly demonstrates the occurrence of flow separation at the elbow, which is a typical effect of high Reynolds flows. Using the obtained flow contraction coefficient, an improved 1D model with nonlinear elbow resistance is proposed and solved by SPH. The 1D SPH results show the best fit with experimental data obtained so far.

scholarly journals Dynamic Response Analysis of Retaining Dam under the Impact of Solid-Liquid Two-Phase Debris Flow Based on the Coupled SPH-DEM-FEM Method

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Bailong Li ◽  
Changming Wang ◽  
Yanying Li ◽  
Yiao Liu ◽  
Nan Jiang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Debris Flow ◽  
Impact Force ◽  
Time History ◽  
Impact Behavior ◽  
Response Analysis ◽  
Two Phase ◽  
Fem Method ◽  
Solid Liquid ◽  
The Impact

Based on the coupled SPH-DEM-FEM numerical method, this paper analyzes the dynamic interaction of solid debris flow particle-liquid debris flow slurry-retaining dam in order to explore the dynamic response of retaining dam under the impact of the solid-liquid two-phase debris flow and delves into the process of the debris flow impact on the dam, the impact force of debris flow, and the elastic-plastic time-history characteristics of the dam under different slopes of trapezoidal grooves. The calculation results show that the coupled SPH-DEM-FEM method can vividly simulate the impact behavior of the solid-liquid two-phase debris flow on the dam, reproduce the impact, climbing, and siltation in the process of the debris flow impact; the dynamic time-history curve of the retaining dam is consistent with the law of the literature, and the result of the debris flow impact force obtained is close to that of the empirical formula. Moreover, this paper studies the impact force distribution of the debris flow impact process. The results have a certain reference value for the study of the dynamic response of the retaining dam under the impact of the solid-liquid two-phase debris flow and the engineering design of the debris flow-retaining dam.

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